Optimization for adaptive antenna arrays with mutually coupled elements via spatially smoothed ESPRIT

The paper presents an adaptive technique for a mutually coupled array. It employs amplitude and phase optimization to create multiple nulls to suppress multiple jammers, and is based on forward/backward smoothed ESPRIT (estimation of signal parameters via rotational invariance technique). Both current amplitudes and phases are simultaneously adjusted to maximize the SIR (signal-to-interference ratio). To take account of mutual coupling, the self and mutual impedances of the array are computed.